Integrated circuit manufacturing processes often provide devices with different breakdown voltages. Sometimes it may be advantageous to use low-voltage devices in a high-voltage portion of the circuit. In that case, the low-voltage device has to be protected against high-voltages. Protecting the drain-source of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device, for example, can be achieved using a high-voltage MOSFET arrangement in which two MOSFETs are stacked. The gate-source voltage can be protected, for example, with multiple diodes connected between the gate and the source.
The inventor has identified several disadvantages in conventional circuits using diodes for protecting the gate-source junction of a low-voltage device, as described further below.